Bone Digestion

Discussion in 'SciFi & Fantasy' started by caters, Aug 16, 2017.

  1. caters Registered Member

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    My Kepler Bb humanoids have a digestive system that is similar to ours but also in 2 anatomical ways, different.

    The 1 anatomical difference that gives these humanoids more energy is, wait for it, their appendix.

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    Now this is a normal human appendix, only a few inches long. But a Kepler Bb humanoid's appendix is at least 3 times as long. With this added length, more good bacteria can be safely tucked away when the humanoid is ill and cellulose can be digested into simple sugars and absorbed into the bloodstream. This coupled with an overall higher BMR(basal metabolic rate) means that they get more energy from the same kinds of food than we do, particularly from plants.

    Now their other anatomical difference related to digestion is that they have 2 stomachs, 1 of which is just like ours and the other being inverted along the L->R axis.

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    As you can see here, the gastric sphincter between the 2 stomachs is right in the middle of the first stomach. Now most of the time, food just gets digested in the first stomach both mechanically and chemically. But there are 3 cases in which the gastric sphincter will open and food will go into the second stomach. 1 of those is gluttony in which the gastric sphincter will stay open until there is a more comfortable amount in the first stomach. The other is illness during which any food that is eaten will go into the second stomach with as little time in the first stomach as possible to avoid vomiting up food. In fact both of these cases are to avoid vomiting up food. But there is 1 other case that is more interesting. Digestion of bone.

    You see, these humanoids eat a lot of bone, especially when they are either children going through growth spurts or pregnant women. Now the lower age limit for eating bone is 5 years and it is that way for a good reason. Any younger than 5 years and the esophagus will literally be scraped to the point of bleeding by eating bone. If this happens, a lot of blood can get into the first stomach and the child will vomit the blood back up. This can aggravate the esophageal scrape and thus worsen the bleeding which leads to more vomiting. While yes, with rehydration therapy the bone will get digested and the esophagus will heal, the child can easily become anemic this way. And yes bone marrow has a high iron content so the anemia would easily be corrected. But it is just not worth it to eat bone when the humanoid is below 5 years old. An anemic humanoid below 5 would be better off eating liver than bone to correct their low iron because then at least there won't be bleeding and vomiting.

    Anyway, the digestion of bone in the second stomach is very slow. Even with the bone digesting enzymes it secretes, it can still take hours to digest the amount of bone in an average meal depending on how thick the bone is. The meat itself, the muscle is digested much faster than this. And even though a higher amount of stomach acid speeds up the process, it doesn't speed it up by all that much. Once the bone has been digested, the gastric sphincter opens to let the second stomach push the digested bone into the first stomach to let it out into the intestines via the pyloric sphincter.

    But I was wondering, is there a better way to digest bone without risking bleeding in the intestines and while still having the defense against vomiting food provided by the second stomach being in the position that it is? Could anything other than enzymes and amount of stomach acid speed up the process?
     
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  3. timojin Valued Senior Member

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  5. timojin Valued Senior Member

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    Eat processed food ( ground meat with bones ). I am not sure if dog food and some food for human consumption does not have some ground bones as a filler.
     
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  7. DaveC426913 Valued Senior Member

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    I think you kind of missed the entire point of the OP's question.

    Pretty sure his humanoids did not evolve to eat processed food.
     
  8. DaveC426913 Valued Senior Member

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    Are you sure you need to go into this level of detail? You may run into a problem explaining their anatomy and metabolism so explicitly. You're going to have to address why a completely alien biology is "the same as ours, with just a few minor exceptions" - as opposed to a very different, though convergent, evolution.
     
  9. Michael 345 Valued Senior Member

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    I was about to post something along the same lines

    Unless it's a critical component of the plot or storyline I don't think your readers will care how your aliens digest bone

    Paint with broad strokes and let readers fill in or not the fine details

    I'm sure you will get communications about bone digestion if readers feel you have missed such a detail and it was somehow important

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  10. DaveC426913 Valued Senior Member

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    Well, I took it as a given that the cultural and nutritive aspects of his humanoids will be an important part of the story.

    I wasn't suggesting glossing over it because it isn't important; I was suggesting keeping it vague for technical, expository reasons, because it opens a very large biophysical can of worms.
     
  11. caters Registered Member

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    But I never plan to write in order to publish, I just write to write so a discussion about how to speed up bone digestion won't stop me from reaching my goals because I don't have any as far as writing is concerned.

    And what do you mean by this biophysical can of worms? I mean, it isn't like their second stomach can't do peristalsis. It just doesn't do it with every meal, same with the appendix. And eating bone is 1 way to correct deficiencies in these minerals:
    • Calcium
    • Phosphorus
    • Iron
    And since these humanoids have not domesticated animals yet, just grown plants, milk, while high in calcium, is rare to come by(unless you are talking about humanoid breastmilk but I don't know if humanoid breastmilk would taste any good to adults or even older children).

    So the only practical solution to getting enough calcium and phosphorus so that the body doesn't have to leech calcium and phosphorus from bones is eating bone. And eating bone and eating organ meats are equally practical in adults and older children for correcting anemia, it is just children below 5 that eating bone is not practical for.

    But of course, organ meats have their risks and I don't just mean infection. 1 major risk of eating organ meats to correct iron levels is vitamin toxicity. This is especially true of Vitamin A because unlike with plants where the body will only metabolize as much of the provitamin beta-carotene as it needs, organ meats have their vitamin A in the form of Retinol, Retinal, or Retanoic Acid, all of which can and will cause Vitamin A toxicity if the organ meat is eaten in excess.
     
  12. DaveC426913 Valued Senior Member

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    I mean story-writing-wise.

    If you start down the path of explaining that level of detail, you may find it's a road you can't come back from. (The same thing tends to happen with technology in stories. once one starts explaining how their star drives work, they often find they box themselves into a corner, having to make other aspects of physics as plausible.)


    But it sounds like you know what your motives are for the depth of detail in story, so I'll desist from second-guessing them.
     

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